Elastic venous compression orthosis

ABSTRACT

An elastic venous compression orthosis having a top part and a leg part, the top part and the leg part having a top part knit thread and leg part knit thread, respectively, defining a network of knitted meshes, and a top part weft thread and leg part weft thread, respectively, each weft thread having a core which is covered by means of a covering thread, the orthosis being characterized in that the core of the top part weft thread and the one or more covering threads of the top part weft thread are made of elastane, and the core of the top part weft thread has a linear density of less than 0.7 times that of the core of the leg part weft thread.

TECHNICAL FIELD

The present invention relates to an elastic venous retention and/orcompression orthosis indicated in cases of vein disorders of a lowerlimb of a patient.

PRIOR ART

Elastic venous retention and/or compression orthoses, formerly known as“retention stockings (or hoses)” or “retention tights”, are textilemedical devices producing a therapeutic effect through retention and/orcompression of the lower limbs, unlike “support stockings” (or even“support hoses” or “anti-fatigue stockings”) and “fashion stockings”,which are not medical devices with a therapeutic purpose.

The orthoses are designed to produce a therapeutic effect throughretention and/or compression of the lower limb over a greater or lesserextent, usually with a pressure profile decreasing upwards from theankle.

To permit strong compression of the lower limbs, the elastic venouscompression orthoses are made from a knitted mesh with incorporation ofan elastic weft thread, generally a covered elastane.

The orthosis is put onto the lower limb of the patient to be treated, asfar as a position of use. The restoring force of the elastic fibres thenexerts a compression.

The mesh and the threads, and the dimensioning of the rows of meshes,are chosen in such a way as to apply predetermined pressures atdifferent altitudes of the lower limb, for example at the height of theankle, at the start of the calf, at the level of the calf, at thepopliteal fossa, etc., as far as the top of the thigh, said altitudesbeing conventionally designated B to G. These different pressures aredefined for each class by reference to metrological jigs such as the legmodel of French standard NF G 30-102 part B, annex B, corresponding tothe “Hohenstein” leg model according to the German standard RAL-GZ 387,or as defined in the experimental European standard XP ENV 12718:2001.

Since the morphology of the lower limbs differs from one patient toanother, an orthosis model is conventionally offered in several sizes inorder to satisfy the target population. A size of a model isconventionally characterized by particular dimensions. The elasticity ofthe orthosis, however, allows one size to fit patients who have lowerlimbs of different dimensions. All the sizes of a model are referred toas a size “grid”.

To limit the costs, the manufacturers of orthoses need to reduce thenumber of size grids.

They also need to be able to manufacture the orthoses using knittingmachines which are as inexpensive as possible and which, in particular,are without specific unwinding systems, like the Memminger ELAN systemsdescribed at the websitehttp://www.memminger-iro.com/en/fournisseure/elan-30.php?thisID=151.

Finally, there is a constant need to improve the effectiveness and thecomfort of the orthoses.

An object of the invention is to meet these needs at least in part.

SUMMARY OF THE INVENTION

According to the invention, this object is achieved by means of anorthosis having a top part, which is preferably ribbed, in French“bord-cote”, hereafter “the top part”, and a leg part,

the top part and the leg part having a top part knit thread, and a legpart knit thread, respectively, defining a network of knitted meshes,and a top part weft thread and leg part weft thread, respectively,

each weft thread having a central thread, or “core”, preferably a singlecore, which is covered, preferably double-covered, by means of acovering thread.

It is notable that the core of the top part weft thread and the one ormore covering threads of the top part weft thread are made of elastane,and the core of the top part weft thread has a linear density (i.e.linear mass density) of less than 0.7 times that of the core of the legpart weft thread.

The inventors have found that an orthosis according to the invention canadapt to a wide sector of the population, which makes it possible toreduce the number of sizes. Surprisingly, without being able to explainthis theoretically, the inventors have additionally discovered that theorthosis may be easily manufactured using standard knitting machines.The investments and the running costs are advantageously limited as aresult. Finally, it is effective and particularly comfortable.

An orthosis according to the invention may also have one or more of thefollowing optional and preferred features:

-   -   the top part knit thread is a single covered thread composed of        an elastane core covered with a covering thread of polyamide;    -   the ratio of the linear density of the core of the leg part weft        thread to the linear density of the core of the top part weft        thread is greater than 2.0;    -   the linear density of the core of the leg part knit thread is        below 45 dTex and over 10 dTex;    -   the top part having a reinforcement thread, which is different        from the top part weft thread and from the top part knit        threadtop part knit thread, extending transversely and having an        elongation at break, measured according to DIN 53834, of below        40%;    -   the reinforcement thread is made of polyamide and has a linear        density of over 30 dTex and below 60 dTex;    -   the top part has an inner cuff and an outer cuff, folded back on        the inner cuff, the reinforcement thread extending exclusively        in the inner cuff;    -   the orthosis is an elastic venous compression orthosis of class        I, II, III or IV, according to the ASQUAL system (<<Référentiel        technique prescrit pour les orthèses élastiques de contention        des membres”, revision n° 5, COFRAC).

The invention also concerns the use of an orthosis according to theinvention for treating a venous disease of lower limb of a patient.

BRIEF DESCRIPTION OF THE FIGURES

Other features and advantages of the invention will become clearer fromreading the following detailed description and from examining theattached drawing, in which:

FIG. 1 is a schematic representation of an orthosis according to theinvention;

FIG. 2 shows the orthosis from FIG. 1 fitted on a lower limb of apatient (position of use);

FIGS. 3a and 3b show a macroscopic view of a detail of the top part andof the leg part, respectively, of the orthosis from FIG. 1;

FIG. 4 is a schematic representation of a detail of a double-coveredthread.

DEFINITIONS

-   -   “Altitude” corresponds to a level in the vertical direction V        when the orthosis is being worn by a patient standing straight        and upright, as is shown in FIG. 2.

DETAILED DESCRIPTION

In FIGS. 1 and 2, reference sign 10 generally designates an orthosisaccording to the invention.

The orthosis 10, having a general anatomical shape, comprises a footpart 12 enclosing the foot, a leg part 13 having an ankle part 14enclosing the ankle and a calf part 16 enclosing the calf, and a knittedend part called the “top part” 18.

The orthosis 10 extends to a level situated below the knee, in the casewhere the orthosis is a “half-hose” (or “knee sock”).

The configuration in the form of a sock is not limiting, and theorthosis 10 may also be produced in the form of a “thigh stocking”,continued by a compressive thigh part 20. The orthosis 10 may also beproduced in the form of tights and/or without a foot part 12 (stockingor tights of the “open foot” type).

The various adjoining parts of the orthosis 10 are preferably knittedcontinuously on a circular machine, according to conventional methods.The production of the orthosis 10 does not require any preparatory stepfor assembling the various parts, except for the operations of sewing onthe foot part 12, if the latter is present.

In FIG. 2, the altitudes of the lower limb as defined by themorphological reference system indicated in the introduction (leg modelor “Hohenstein jig”) have been shown using standard notation:

-   -   B: ankle, at the point of its smallest circumference;    -   B1: junction between the Achilles tendon and the calf muscles;    -   C: calf, at the point of its greatest circumference;    -   D: just below the tibial tuberosity (that is to say just below        the knee);    -   E: at the centre of the knee cap and above the back of the knee        (that is to say at the level of the popliteal fosse);    -   F: at the middle of the thigh; and    -   G: at the top of the thigh.

The calf is the limb segment situated between levels B1 and D, and theankle is the limb segment situated below level B1.

As is shown in FIG. 3, the top part 18 conventionally has a network ofmeshes 22 produced by means of a top part knit thread 24, a top partweft thread 26 being interlaced between said meshes.

The leg part 13 also conventionally has a network of meshes 32 producedby means of a leg part knit thread 34, a leg part weft thread 36 beinginterlaced between said meshes.

The nature of the threads and of the meshes is adapted depending on thedesired action for the different parts of the orthosis, in particulardepending on whether the action is to be one of retention orcompression. This adaptation does not pose any particular difficulty toa person skilled in the art.

For an elastic venous compression orthosis, the pressure measured at theankle may in particular vary from 10 to over 36 mmHg (i.e. 13 to 48 hPa,although mmHg is commonly used as the unit of measurement of pressure inthe field of phlebology and of medical compression).

The elastic venous compression orthoses are divided into four textileclasses according to the ASQUAL system, from class I (13 to 20 hPa≈10 to15 mmHg at the ankle) to class IV (>48 hPa≈>36 mmHg at the ankle).

A weft thread conventionally extends transversely with respect to theprincipal axis X of the orthosis, shown in FIG. 1. More precisely, itextends orthoradially, spiralling about the principal axis of theorthosis and passing along the rows of meshes.

Top Part

Preferably, the top part 18 is a so-called “double cuff” structure, thatis to say the result of the orthosis neck (which defines the openingthrough which the orthosis is put on) being folded over inwards orpreferably outwards from the orthosis. It thus has an inner cuff 18 _(i)intended to be in contact with the skin of the lower limb of thepatient, and an outer cuff 18 _(e) exposed to the outside and separatedfrom the skin by the inner cuff.

In a preferred embodiment, the top part knit thread 24 is a singlecovered thread composed of an elastane core A covered with one or morecovering threads C of polyamide (see FIG. 4).

Preferably, the linear density of the core of the top part knit thread24 is below 45 dTex, preferably below 30 dTex, preferably below 25 dTex,preferably below 20 dTex, and/or above 10 dTex, preferably above 15dTex.

Preferably, the linear density of the covering thread of the top partknit thread 24 is below 60 dTex, preferably below 50 dTex, preferablybelow 45 dTex, and/or above 20 dTex, preferably above 30 dTex,preferably above 40 dTex.

In one embodiment, the top part has only a single weft thread.

In a preferred embodiment, the top part weft thread 26 is a coveredthread, preferably a double-covered thread.

The top part weft thread 26 is composed of a core of elastane coveredwith an elastane covering thread, preferably double-covered with one ormore elastane covering threads. The double covering of elastanefacilitates the knitting of the orthosis.

Preferably, all the covering thread of top part weft thread 26 are madeof elastane.

Without being bound by this theory, the inventors consider that theelasticity of the covering thread prevents the covering thread fromlimiting the capacities of elastic deformation of the weft thread.

Advantageously, a top part weft thread 26 composed of an elastane coredouble-covered with an elastane covering thread may be used like theconventional weft threads, without a specific unwinding system, incontrast in particular to simple threads of elastane.

Preferably, the linear density of the core of the top part weft thread26 is below 150 dTex, preferably below 140 dTex, preferably below 135dTex, and/or above 100 dTex, preferably above 110 dTex, preferably above120 dTex, preferably above 125 dTex.

Preferably, the linear density of the covering thread of the top partweft thread 26 is below 40 dTex, preferably below 30 dTex, preferablybelow 25 dTex, and/or above 10 dTex, preferably above 15 dTex,preferably above 20 dTex.

In a preferred embodiment, the top part moreover has a reinforcementthread 40, which is different from the weft thread and from the knitthread and which extends transversely, like the weft thread.

In one embodiment, the top part has only a single reinforcement thread.

Preferably, the reinforcement thread does not extend over a thigh partand/or an ankle part and/or a calf part and/or a foot part that areintended to enclose a thigh, an ankle, a calf and a foot, respectively,of a patient wearing the orthosis.

Preferably, the reinforcement thread extends exclusively in the toppart, preferably over more than 90%, preferably over substantially 100%of the height of the top part. Advantageously, the presence of thereinforcement thread in the top part alone does not modify thebehaviour, in particular the elasticity, of the parts of the orthosisthat extend below the top part.

Preferably, the reinforcement thread 40 only extends in the inner cuff18 _(i) of the top part. Comfort is thereby improved.

Preferably, the reinforcement thread 40 has an elongation at break ofbelow 40%, preferably of below 35%, preferably of below 30%, preferablyof below 28%, preferably of below 27%. The elongation at break may bemeasured according to DIN 53834.

The reinforcement thread 40 is preferably of polyamide. Preferably, thereinforcement thread 40 is a “simple” thread, i.e. not covered.

It preferably has a linear density of over 30 dTex, preferably of over35 dTex, preferably of over 40 dTex and/or below 60 dTex, preferablybelow 50 dTex, more preferably below 45 dTex.

The inventors have found that the presence of such a reinforcementthread very substantially improves the resistance to folds in the toppart, without impairing the comfort. Now the folds are high-pressurezones which impair the effectiveness of the orthosis.

Leg Part

The leg part knit thread may be identical or different depending on theportion of the leg part in question. In particular, it may be differentin the ankle part 14 and calf part 16.

The knit thread may be identical in the calf part 16 and thigh part 20,and/or in the ankle part 14 and thigh part 20.

In one embodiment, the leg part has only a single knit thread.

In a preferred embodiment, the leg part knit thread 34 is a singlecovered thread composed of an elastane core covered with one or morecovering threads of polyamide.

Preferably, the linear density of the core of the leg part knit thread34 is below 45 dTex, preferably below 30 dTex, preferably below 25 dTex,preferably below 20 dTex, and/or over 10 dTex, preferably over 15 dTex.

Preferably, the linear density of the covering thread of the leg partknit thread 34 is below 60 dTex, preferably below 50 dTex, preferablybelow 45 dTex, and/or over 20 dTex, preferably over 30 dTex, preferablyover 40 dTex.

In one embodiment, the leg part has only a single weft thread.

In a preferred embodiment, the leg part weft thread 36 is a doublecovered thread composed of an elastane core covered with a coveringthread of polyamide. Advantageously, such a covering thread makes theorthosis easier to put on.

Preferably, the ratio of the linear density of the core of the leg partweft thread 36 to the linear density of the core of the top part weftthread 26 is over 1.9, preferably over 2.0, preferably over 2.1,preferably over 2.2, preferably over 2.3, and/or below 3.0, preferablybelow 2.8, preferably below 2.6, preferably below 2.5, preferably below2.4.

Preferably, the linear density of the core of the leg part weft thread36 is below 350 dTex, preferably below 340 dTex, and/or over 250 dTex,preferably over 280 dTex, preferably over 290 dTex, preferably over 300dTex, preferably over 320 dTex.

Preferably, the linear density of the covering thread of the leg partweft thread 36 is below 40 dTex, preferably below 30 dTex, preferablybelow 25 dTex, and/or over 10 dTex, preferably over 15 dTex, preferablyover 20 dTex.

In a preferred embodiment, the leg part has no reinforcement thread,like the top part.

Of course, the invention is not limited to the embodiments described andshown, which are provided for illustrative purposes only.

The invention claimed is:
 1. Elastic venous retention and/or compressionorthosis having a top part and a leg part, the top part and the leg parthaving a top part knit thread and leg part knit thread, respectively,defining a network of knitted meshes, and a top part weft thread and legpart weft thread, respectively, each weft thread having a core which iscovered by means of a covering thread, the orthosis being characterizedin that the core of the top part weft thread and the covering thread ofthe top part weft thread are made of elastane, and the core of the toppart weft thread has a linear density of less than 0.7 times that of thecore of the leg part weft thread.
 2. Orthosis according to claim 1, thecore of the top part weft thread being double-covered by means of acovering thread of elastane.
 3. Orthosis according to claim 1, the toppart knit thread being a single covered thread composed of an elastanecore covered with a covering thread of polyamide.
 4. Orthosis accordingto claim 1, the ratio of the linear density of the core of the leg partweft thread to the linear density of the core of the top part weftthread being greater than 2.0.
 5. Orthosis according to claim 1, thelinear density of the core of the leg part knit thread being below 45dTex and over 10 dTex.
 6. Orthosis according to claim 1, the top parthaving a reinforcement thread, which is different from the top part weftthread and from the top part knit thread, the reinforcement threadhaving an elongation at break, measured according to norm DIN 53834, ofbelow 40%.
 7. Orthosis according to claim 6, the reinforcement threadbeing made of polyamide and having a linear density of over 30 dTex andbelow 60 dTex.
 8. Orthosis according to claim 6, the top part having aninner cuff and an outer cuff folded back on the inner cuff, thereinforcement thread extending exclusively in the inner cuff.
 9. Elasticvenous compression orthosis according to claim 1, of class I, II, III orIV, according to the ASQUAL system.